Golf club head

ABSTRACT

Provided is a head including a striking face forming portion and a rib frame that is constituted by a plurality of extending portions. The rib frame and the striking face forming portion constitute a head structure portion. The head structure portion includes a first shape portion having a shape corresponding to a first constituent face that is arbitrarily selected from a semi-regular polyhedron, and a second shape portion having a shape corresponding to a second constituent face that shares one side with the first constituent face in the semi-regular polyhedron. The first constituent face may be a triangle, a quadrangle, or a pentagon. The semi-regular polyhedron may be an icosidodecahedron, for example. Alternatively, the semi-regular polyhedron may be a cuboctahedron, for example.

The present application claims priority on Patent Application No. 2018-50929 filed in Japan on Mar. 19, 2018, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to a golf club head.

Description of the Related Art

JPH04-347179A discloses a framework body including a frame member that extends substantially arcuately and connects a heel side portion and a toe side portion of a rear surface of a face wall body.

SUMMARY OF THE INVENTION

If enhancement in rigidity of a larger head with less weight can be achieved, design freedom of the head is improved.

The present disclosure provides a structure that can improve design freedom of a head.

A golf club head according to one aspect includes a striking face forming portion and a rib frame that is constituted by a plurality of extending portions. The rib frame and the striking face forming portion constitute a head structure portion. The head structure portion includes a first shape portion having a shape corresponding to a first constituent face that is arbitrarily selected from a semi-regular polyhedron, and a second shape portion having a shape corresponding to a second constituent face that shares one side with the first constituent face in the semi-regular polyhedron.

A golf club head according to another aspect includes a striking face forming portion and a rib frame that is constituted by at least three extending portions. The rib frame includes a triangular portion that has a shape corresponding to a triangle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a head according to a first embodiment;

FIG. 2 is a plan view of a head structure portion of the head in FIG. 1;

FIG. 3 is a bottom view of the head structure portion of the head in FIG. 1;

FIGS. 4A and 4B are perspective views of an icosidodecahedron;

FIG. 5 is the same plan view as FIG. 2, and shows an approximate triangle using dashed-line hatching and an approximate pentagon using solid-line hatching;

FIG. 6 shows correspondence between the embodiment of FIG. 5 and a semi-regular polyhedron;

FIG. 7 is the same bottom view as FIG. 3, and shows an approximate triangle using dashed-line hatching and an approximate pentagon using solid-line hatching;

FIG. 8 shows correspondence between the embodiment of FIG. 7 and a semi-regular polyhedron;

FIG. 9 is the same plan view as FIG. 5;

FIG. 10 is the same bottom view as FIG. 7;

FIG. 11 shows correspondence between the embodiment of FIGS. 9 and 10 and a semi-regular polyhedron;

FIG. 12 is a plan view of a head according to a second embodiment;

FIG. 13 is a plan view of a head structure portion of the head in FIG. 12;

FIG. 14 is a back view of the head structure portion of the head in FIG. 13;

FIGS. 15A and 15B are perspective views of a cuboctahedron;

FIG. 16 is the same back view as FIG. 14, and shows an approximate triangle using dashed-line hatching and an approximate pentagon using solid-line hatching;

FIG. 17 shows correspondence between the embodiment of FIG. 16 and a semi-regular polyhedron;

FIG. 18 is a schematic diagram of a head structure portion to which an icosidodecahedral structure is applied;

FIG. 19 is a schematic diagram of a head structure portion to which a cuboctahedral structure is applied;

FIG. 20 is a schematic diagram of a head structure portion to which a rhombicuboctahedral structure is applied;

FIGS. 21A to 21F are cross-sectional views showing examples of the configuration of a rib frame; and

FIG. 22 is a diagram for illustrating a toe-heel direction and a face-back direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following describes embodiments of the present disclosure in detail with reference to the accompanying drawings as appropriate.

In the present application, a reference state, a reference perpendicular plane, a face-back direction, a toe-heel direction, and an up-down direction are defined as follows. The reference state is a state where a head is placed at a predetermined lie angle and real loft angle on a horizontal plane HP. As shown in FIG. 22, in the reference state, a center line Z of a hosel hole is contained in a plane VP perpendicular to the horizontal plane HP. The plane VP is defined as the reference perpendicular plane. The predetermined lie angle and real loft angle are shown in a product catalog, for example.

In the present application, the toe-heel direction is a direction of an intersection line NL between the reference perpendicular plane VP and the horizontal plane HP (see FIG. 22).

In the present application, the face-back direction is a direction perpendicular to the toe-heel direction and parallel to the horizontal plane HP.

In the present application, the up-down direction is a direction perpendicular to the toe-heel direction and perpendicular to the face-back direction. In other words, the up-down direction in the present application is a direction perpendicular to the horizontal plane HP.

First Embodiment

FIG. 1 is a plan view of a golf club head 2 according to the first embodiment as viewed from a crown side. The head 2 includes a striking face 4, a crown 6, a sole 8, and a hosel 10. The hosel 10 includes a hosel hole 12. The head 2 is a wood-type head. Although not shown in FIG. 1, the head 2 has a hollow structure. The inside of the head 2 is an empty space. In other words, the head 2 includes an outer shell portion and a hollow portion.

The head 2 is formed by joining a cover member c1 to a head body h1. FIG. 2 is a plan view of the head body h1 as viewed from the crown side. FIG. 3 is a bottom view of the head body h1 as viewed from the sole side.

As is clear from comparison between FIGS. 1 and 2, the head 2 includes the head body h1 and the cover member c1 joined to the head body h1. The cover member c1 constitutes a part of the outer shell portion of the head 2. A crown cover member c11 and a sole cover member c12 are used as the cover member c1 in the head 2.

The crown 6 has an outer surface forming a convex curved surface. The crown cover member c11 is a plate-shaped member that is curved to conform to the shape of the crown 6. The crown cover member c11 constitutes a part (major part) of the outer surface of the crown 6. A boundary line k1 shown in FIG. 1 is the contour of the crown cover member c11. The sole cover member c12 is a plate-shaped member that is curved to conform to the shape of the sole 8. The sole cover member c12 constitutes a part (major part) of an outer surface of the sole 8. These cover members c1 makes the inside of the head 2 invisible. In the present embodiment, a rib frame (described later) is invisible in the finished head 2.

The material of the cover member c1 is different from the material of the head body h1. In the head 2, the head body h1 is made of a metal and the cover member c1 is made of a nonmetal. The cover member c1 can be made of a carbon fiber reinforced plastic (CFRP), for example. The head body h1 and the cover member c1 are glued to each other with an adhesive agent. The cover member c1 may be made of a metal. The cover member c1 may be welded to the head body h1.

The head 2 includes a striking face forming portion 14. The striking face forming portion 14 includes at least a part of the striking face 4. In the present embodiment, the striking face forming portion 14 includes the whole of the striking face 4. The striking face forming portion 14 includes a flange portion 16 extending from the striking face 4 toward the back side. The flange portion 16 constitutes a part of the crown 6 (a part near the face). The flange portion 16 constitutes a part of the sole 8 (a part near the face). In the head 2, the striking face forming portion 14 as a whole has a cup shape whose bottom surface is the striking face 4. Ends of extending portions (described later) of the rib frame can be connected to the striking face forming portion 14 (flange portion 16).

A double-pointed arrow L1 in FIG. 2 shows a length of the striking face forming portion 14 in the face-back direction. This length L1 is preferably equal to or less than 40 mm, more preferably equal to or less than 35 mm, and still more preferably equal to or less than 30 mm. In view of the size and loft angle of the striking face 4, the length L1 is preferably equal to or greater than 10 mm, and more preferably equal to or greater than 15 mm. The striking face forming portion 14 need not include the flange portion 16. For example, the striking face forming portion 14 may have a plate shape. The striking face forming portion 14 can be connected to ends of extending portions E1 (described later) of the rib frame.

As shown in FIGS. 2 and 3, the head 2 includes a rib frame 20. The rib frame 20 includes a plurality of extending portions E1. In FIGS. 2 and 3, the extending portions E1 extend so as to form respective strips. The rib frame 20 is constituted by three or more extending portions E1. “Extending portion” is a concept that includes a rib and a frame.

The head 2 includes a head structure portion s1. The head structure portion s1 is constituted by the striking face forming portion 14 and the rib frame 20. The rib frame 20 is located on the back side relative to the striking face forming portion 14. In the present embodiment, the head structure portion s1 is identical to the head body h1. The head structure portion s1 is made of a metal.

The rib frame 20 includes an intersection portion 22 at which the extending portions E1 intersect with each other. A plurality of intersection portions 22 are provided. Each intersection portion 22 is formed by two extending portions E1 intersecting with each other. There is no intersection portion at which three or more extending portions E1 intersect. Three or more extending portions E1 do not intersect at a single point so that the number of the intersection portions 22 is increased, whereby the degree of similarity to a semi-regular polyhedron increases. The increased number of the intersection portions 22 can increase the number of triangular portions. The semi-regular polyhedron and the triangular portion will be described later.

As shown in FIGS. 2 and 3, the rib frame 20 includes a first extending portion E11, a second extending portion E12, and a third extending portion E13 as the extending portions E1. The rib frame 20 further includes a fourth extending portion E14 and a fifth extending portion E15.

In the crown 6, the first extending portion E11 is connected to the striking face forming portion 14 at a position in a toe-side half of the striking face forming portion 14 (see FIG. 2). In the crown 6, the first extending portion E11 extends while inclining so as to go toward the heel side as it goes to the back side. The first extending portion E11 further extends from the crown 6 into the sole 8 while intersecting with the fifth extending portion E15. In the sole 8, the first extending portion E11 is connected to the striking face forming portion 14 at a position in a heel-side half of the striking face forming portion 14 (see FIG. 3). In the sole 8, the first extending portion E11 extends while inclining so as to go toward the heel side as it goes to the face side (see FIG. 3).

In the crown 6, the second extending portion E12 is connected to the striking face forming portion 14 at a position in the heel-side half of the striking face forming portion 14 (see FIG. 2). In the crown 6, the second extending portion E12 extends while inclining so as to go toward the toe side as it goes to the back side. The second extending portion E12 further extends from the crown 6 into the sole 8 while intersecting with the fifth extending portion E15. In the sole 8, the second extending portion E12 is connected to the striking face forming portion 14 at a position in the toe-side half of the striking face forming portion 14 (see FIG. 3). In the sole 8, the second extending portion E12 extends while inclining so as to go toward the toe side as it goes to the face side (see FIG. 3).

In the crown 6, the third extending portion E13 is connected to the striking face forming portion 14 at a position in the heel-side half of the striking face forming portion 14 (see FIG. 2). In the crown 6, the third extending portion E13 is located on the heel side relative to the second extending portion E12. In the crown 6, the third extending portion E13 extends while inclining so as to go toward the heel side as it goes to the backside. The third extending portion E13 further extends from the crown 6 into the sole 8 while intersecting with the fifth extending portion E15. In the sole 8, the third extending portion E13 is connected to the striking face forming portion 14 at a position in the toe-side half of the striking face forming portion 14 (see FIG. 3). In the sole 8, the third extending portion E13 is connected to the striking face forming portion 14 at a position on the toe side relative to the second extending portion E12. In the sole 8, the third extending portion E13 extends while inclining so as to go toward the toe side as it goes to the face side (see FIG. 3).

The fourth extending portion E14 is not present in the crown 6. The fourth extending portion E14 is present only in the sole. In the sole 8, the fourth extending portion E14 is connected to the striking face forming portion 14 at a position in the heel-side half of the striking face forming portion 14 (see FIG. 3). In the sole 8, the fourth extending portion E14 is connected to the striking face forming portion 14 at a position on the heel side relative to the first extending portion E11. In the sole 8, the fourth extending portion E14 extends while inclining so as to go toward the heel side as it goes to the face side (see FIG. 3).

The fifth extending portion E15 extends along a boundary k2 between the crown 6 and the sole 8. The fifth extending portion E15 extends from a toe-side end of the striking face forming portion 14 to a heel-side end of the striking face forming portion 14.

Note that, although a space between the extending portions E1 is filled with a weight member W1 and so on in a back-side portion of the sole 8 (see FIG. 3), each extending portion E1 protrudes from the inner surface of the head (see FIG. 2) and therefore can be recognized as being continuously extending.

Each extending portion E1 may be straight or curved. In the present embodiment, the extending portions E11 to E15 are curved. Each extending portion E1 is curved along the external shape of the head 2 (along the crown 6 or the sole 8) and is also curved in plan views.

The extending portions E11 to E13 are bent along the external shape of the head to form respective corners at the boundary k2 between the crown 6 and the sole 8. Except for the corners formed at the boundary k2, each extending portion E1 does not have a corner formed by bending. Except for the corners formed at the boundary k2, each extending portion E1 extends along a smooth curve. Each extending portion E1 is curved with a relatively large radius of curvature. The radius of curvature of each extending portion E1 is preferably equal to or greater than 50.0 mm, and more preferably equal to or greater than 55.0 mm in a plan view from a viewpoint at which the radius of curvature is observed to be minimum. The radius of curvature may be infinite. That is, the extending portions E1 may be straight.

[Semi-Regular Polyhedron]

A semi-regular polyhedral structure is incorporated into the rib frame 20. There are 13 types of semi-regular polyhedrons as listed below.

Truncated tetrahedron

Truncated cube

Truncated octahedron

Truncated dodecahedron

Truncated icosahedron

Cuboctahedron

Icosidodecahedron

Rhombicuboctahedron

Rhombicosidodecahedron

Rhombitruncated cuboctahedron

Rhombitruncated icosidodecahedron

Snub cube

Snub dodecahedron

The semi-regular polyhedrons include quasi-regular polyhedrons. The quasi-regular polyhedrons are the icosidodecahedron and the cuboctahedron.

An icosidodecahedral structure is incorporated into the head structure portion s1 of the head 2. The icosidodecahedral structure is incorporated into the rib frame 20 of the head 2.

FIGS. 4A and 4B are perspective views of an icosidodecahedron 100. The icosidodecahedron 100 has constituent faces consisting of 20 triangles (regular triangles) and 12 pentagons (regular pentagons).

[First Constituent Face, Second Constituent Face, Third Constituent Face]

A first constituent face 101 is selected from the icosidodecahedron 100. The first constituent face 101 is one of the sum of 32 constituent faces. An arbitrary constituent face is selected from among the 32 constituent faces. The first constituent face 101 of the icosidodecahedron is either a pentagon or a triangle. For example, a pentagon may be selected as the first constituent face 101. FIG. 4A shows a case where the first constituent face 101 is a pentagon. Alternatively, a triangle may be selected as the first constituent face 101. FIG. 4B shows a case where the first constituent face 101 is a triangle.

The selection of the first constituent face 101 determines a second constituent face 102. The second constituent face 102 is a constituent face that shares one side with the first constituent face 101.

In FIG. 4A, the second constituent face 102 is a triangle. In FIG. 4A, five second constituent faces 102 are present. That is, the maximum possible number of the second constituent faces 102 is five in this case.

Note that the maximum possible number is determined by the type of the semi-regular polyhedron and the polygon selected as the first constituent face 101. When the first constituent face 101 is an n-sided polygon, the maximum possible number of the second constituent faces 102 is n. Note that n is an integer equal to or larger than three.

In FIG. 4B, the second constituent face 102 is a pentagon. In FIG. 4B, three second constituent faces 102 are present. That is, the maximum possible number of the second constituent faces 102 is three in this case.

The determination of the second constituent faces 102 determines a third constituent face 103. The third constituent face 103 is a constituent face other than the first constituent face 101 and the second constituent faces 102, and has two sides respectively shared with two second constituent faces 102 adjacent to each other. The third constituent face 103 is located between two second constituent faces 102 adjacent to each other.

Note that the third constituent face 103 of the icosidodecahedron is a constituent face other than the second constituent faces 102 and shares one vertex with the first constituent face 101. This definition also applies to the cuboctahedron and the rhombicuboctahedron.

In FIG. 4A, the third constituent face 103 is a pentagon. In FIG. 4A, five third constituent faces 103 are present. That is, the maximum possible number of the third constituent faces 103 is five in this case.

In FIG. 4B, the third constituent face 103 is a triangle. In FIG. 4B, three third constituent faces 103 are present. That is, the maximum possible number of the third constituent faces 103 is three in this case.

FIG. 5 is the same plan view as FIG. 2. FIG. 6 is a diagram showing correspondence between the embodiment of FIG. 5 and the icosidodecahedron 100. FIG. 7 is the same bottom view as FIG. 3. FIG. 8 is a diagram showing correspondence between the embodiment of FIG. 7 and the icosidodecahedron 100. Note that lines that can be seen in the back are erased in FIGS. 5 to 8 unlike in FIGS. 2 and 3.

FIGS. 5 to 8 show an approximate triangle TR by using dashed-line hatching and an approximate pentagon PE by using solid line hatching. The approximate triangle TR is formed by three extending portions E1 or formed by two extending portions E1 and (an edge of) the striking face forming portion 14. The approximate triangle TR has three corners. The approximate pentagon PE is formed by five extending portions E1 or formed by four extending portions E1 and (an edge of) the striking face forming portion 14. The approximate pentagon PE has five corners. The term “approximate” in the “approximate triangle” and “approximate pentagon” is used for accepting the curvature of the extending portions E1.

As shown in FIG. 5, a plurality of (two) approximate triangles TR are formed in the crown 6. A first approximate triangle TR1 and a second approximate triangle TR2 are formed as the approximate triangles TR in the crown 6. As shown in FIG. 7, a plurality of (four) approximate triangles TR are formed in the sole 8. A third approximate triangle TR3, a fourth approximate triangle TR4, a fifth approximate triangle TR5, and a sixth approximate triangle TR6 are formed as the approximate triangles TR in the sole 8. Thus, the six approximate triangles TR are formed in the head structure portion s1.

As shown in FIG. 5, one approximate pentagon PE is formed in the crown 6. A first approximate pentagon PE1 is formed as the approximate pentagon PE in the crown 6. As shown in FIG. 7, three approximate pentagons PE are formed in the sole 8. A second approximate pentagon PE2, a third approximate pentagon PE3, and a fourth approximate pentagon PE4 are formed as the approximate pentagons PE in the sole 8. Thus, the four approximate pentagons PE are formed in the head structure portion s1.

[First Shape Portion, Second Shape Portion, Third Shape Portion]

The head structure portion s1 includes a first shape portion 201 having a shape corresponding to the first constituent face 101, and second shape portions 202 each having a shape corresponding to the second constituent face 102. The head structure portion s1 further includes third shape portions 203 each having a shape corresponding to the third constituent face 103. The following describes a case where the first constituent face 101 is a triangle as in FIG. 4B (see FIGS. 5-6 and 7-8) and a case where the first constituent face 101 is a pentagon as in FIG. 4A (see FIGS. 9-11).

When a triangle is selected as the first constituent face 101, the shape corresponding to the first constituent face 101 is an approximate triangle TR, and the shape corresponding to the second constituent face 102 is an approximate pentagon PE. When a plurality of approximate triangles TR are present as in the present embodiment, any one of the approximate triangles TR may be the first shape portion 201.

For example, as shown in FIG. 7, the third approximate triangle TR3 located in the center of the sole 8 is selected as the first shape portion 201. The three extending portions E1 located to surround the third approximate triangle TR3 constitute the first shape portion 201. In this case, the second shape portions 202 each having the shape corresponding to the second constituent face 102 are the second approximate pentagon PE2, the third approximate pentagon PE3, and the fourth approximate pentagon PE4. In this case, the third shape portions 203 each having the shape corresponding to the third constituent face 103 are the fourth approximate triangle TR4, the fifth approximate triangle TR5, and the sixth approximate triangle TR6.

FIG. 8 shows the embodiment of FIG. 7 by denoting corresponding portions with the same reference signs. That is, the first constituent face 101 and the first shape portion 201 are denoted by A, the second constituent faces 102 and the second shape portions 202 are denoted by B, and the third constituent faces 103 and the third shape portions 203 are denoted by C.

Alternatively, as shown in FIG. 5, for example, the first approximate triangle TR1 located in the center of the crown 6 is selected as the first shape portion 201. The two extending portions E1 and the edge of the striking face forming portion 14 located to surround the first approximate triangle TR1 constitute the first shape portion 201. In this case, the second shape portion 202 having the shape corresponding to the second constituent face 102 is the first approximate pentagon PE1. In this case, the third shape portion 203 having the shape corresponding to the third constituent face 103 is the second approximate triangle TR2.

FIG. 6 shows the embodiment of FIG. 5 by denoting corresponding portions with the same reference signs. That is, the first constituent face 101 and the first shape portion 201 are denoted by A, the second constituent face 102 and the second shape portion 202 are denoted by B, and the third constituent face 103 and the third shape portion 203 are denoted by C.

Note that, in the head structure portion s1, a portion that corresponds to the approximate triangle TR is also referred to as a triangular portion, and a portion that corresponds to the approximate pentagon PE is also referred to as a pentagonal portion. When a triangle is selected as the first constituent face 101, the first shape portion 201 is a triangular portion, the second shape portion 202 is a pentagonal portion, and the third shape portion 203 is a triangular portion.

When a pentagon is selected as the first constituent face 101, the shape corresponding to the first constituent face 101 is an approximate pentagon PE, and the shape corresponding to the second constituent face 102 is an approximate triangle TR. When a plurality of approximate pentagons PE are present as in the present embodiment, any one of the approximate pentagons PE may be the first shape portion 201.

FIG. 9 is the same plan view as FIG. 5. FIG. 10 is the same plan view as FIG. 7. FIG. 11 is a diagram showing correspondence between the embodiment of FIGS. 9 and 10 and the icosidodecahedron 100.

FIGS. 9 and 10 show the case where the second approximate pentagon PE2 is the first shape portion 201. The first shape portion 201 is constituted by the five extending portions E1 (E11, E12, E13, E14, and E15) located to surround the second approximate pentagon PE2. In this case, the second approximate triangle TR2, the third approximate triangle TR3, the fourth approximate triangle TR4, and the sixth approximate triangle TR6 are the second shape portions 202. In this case, the first approximate pentagon PE1, the third approximate pentagon PE3, and the fourth approximate pentagon PE4 are the third shape portions 203. Thus, when a pentagon is selected as the first constituent face 101, the first shape portion 201 is a pentagonal portion, the second shape portions 202 are triangular portions, and the third shape portions 203 are pentagonal portions.

Further, in this case, a fourth shape portion 204 is present. In the present embodiment, the first approximate triangle TR1 is the fourth shape portion 204. The fourth shape portion 204 has a shape corresponding to a fourth constituent face 104 of the semi-regular polyhedron.

FIG. 11 shows the embodiment of FIGS. 9 and 10 by denoting corresponding portions with the same reference signs. That is, the first constituent face 101 and the first shape portion 201 are denoted by A, the second constituent faces 102 and the second shape portions 202 are denoted by B, the third constituent faces 103 and the third shape portions 203 are denoted by C, and the fourth constituent face 104 and the fourth shape portion 204 are denoted by D. The fourth constituent face 104 is a constituent face other than the first constituent face 101, the second constituent faces 102, and the third constituent faces 103, and has two sides respectively shared with two third constituent faces 103 adjacent to each other. The fourth constituent face 104 is located between two third constituent faces 103 adjacent to each other. In the icosidodecahedron 100, the fourth constituent face 104 shares one vertex with one second constituent face 102.

Second Embodiment

FIG. 12 is a plan view of a head 200 according to the second embodiment as viewed from the crown side. The head 200 includes a striking face 4, a crown 6, a sole 8, and a hosel 10. The hosel 10 includes a hosel hole 12. The head 200 is a wood-type head.

The head 200 is formed by joining a cover member c1 to a head body h1. FIG. 13 is a plan view of the head body h1 as viewed from the crown side. FIG. 14 shows the head body h1 as viewed from the back side.

As is clear from comparison between FIGS. 12 and 13, the head 200 includes the head body h1 and the cover member c1 joined to the head body h1. The cover member c1 constitutes a part of an outer shell portion of the head 200. As with the head 2, a crown cover member and a sole cover member are used as the cover member c1 in the head 200.

The head 200 includes a striking face forming portion 14. The striking face forming portion 14 includes the whole of the striking face 4. The striking face forming portion 14 includes a flange portion 16 that extends from the striking face 4 toward the back side.

The head 200 includes a head structure portion s1. The head structure portion s1 is constituted by the striking face forming portion 14 and a rib frame 20. In the present embodiment, the head structure portion s1 is identical to the head body h1. The head structure portion s1 is made of a metal.

As shown in FIGS. 13 and 14, the head 200 includes the rib frame 20. The rib frame 20 includes a plurality of extending portions E1. The rib frame 20 includes an intersection portion 22 at which the extending portions E1 intersect with each other. A plurality of intersection portions 22 are provided.

The rib frame 20 is constituted by three extending portions E1. As shown in FIGS. 13 and 14, the rib frame 20 includes a first extending portion E11, a second extending portion E12, and a third extending portion E13 as the extending portions E1.

In the crown 6, the first extending portion E11 is connected to the striking face forming portion 14 at a position in a toe-side half of the striking face forming portion 14. The first extending portion E11 further extends from the crown 6 into the sole 8 while intersecting with the third extending portion E13. In the sole 8, the first extending portion E11 is connected to the striking face forming portion 14 at a position in a heel-side half of the striking face forming portion 14.

In the crown 6, the second extending portion E12 is connected to the striking face forming portion 14 at a position in the heel-side half of the striking face forming portion 14. The second extending portion E12 further extends from the crown 6 into the sole 8 while intersecting with the third extending portion E13. In the sole 8, the second extending portion E12 is connected to the striking face forming portion 14 at a position in the toe-side half of the striking face forming portion 14. The first extending portion E11 and the second extending portion E12 intersect at a position on the sole side relative to the third extending portion E13.

The third extending portion E13 extends along a boundary k2 between the crown 6 and the sole 8. The third extending portion E13 extends from a toe-side end of the striking face forming portion 14 to a heel-side end of the striking face forming portion 14.

A cuboctahedral structure is incorporated into the head structure portion s1 of the head 200. The cuboctahedral structure is incorporated into the rib frame 20 of the head 200.

FIGS. 15A and 15B are perspective views of a cuboctahedron 300. The cuboctahedron 300 has constituent faces consisting of eight triangles (regular triangles) and six quadrangles (squares).

A first constituent face 301 is selected from the cuboctahedron 300. The first constituent face 301 is one of the sum of 14 constituent faces. An arbitrary constituent face is selected from among the 14 constituent faces. The first constituent face 301 of the cuboctahedron is either a quadrangle or a triangle. For example, a quadrangle may be selected as the first constituent face 301. FIG. 15A shows a case where the first constituent face 301 is a quadrangle. Alternatively, a triangle may be selected as the first constituent face 301. FIG. 15B shows a case where the first constituent face 301 is a triangle.

The selection of the first constituent face 301 determines a second constituent face 302.

In FIG. 15A, the second constituent face 302 is a triangle. In FIG. 15A, four second constituent faces 302 are present. That is, the maximum possible number of the second constituent faces 302 is four in this case.

In FIG. 15B, the second constituent face 302 is a quadrangle. In FIG. 15B, three second constituent faces 302 are present. That is, the maximum possible number of the second constituent faces 302 is three in this case.

The determination of the second constituent faces 302 determines a third constituent face 303. In FIG. 15A, the third constituent face 303 is a quadrangle. In FIG. 15A, four third constituent faces 303 are present. That is, the maximum possible number of the third constituent faces 303 is four in this case.

In FIG. 15B, the third constituent face 303 is a triangle. In FIG. 15B, three third constituent faces 303 are present. That is, the maximum possible number of the third constituent faces 303 is three in this case.

FIG. 16 is the same view as FIG. 14. FIG. 16 shows an approximate triangle TR by using dashed-line hatching and an approximate quadrangle QU by using solid-line hatching. A plurality of (two) approximate triangles TR are formed in the crown 6. A first approximate triangle TR1 and a second approximate triangle TR2 are formed as the approximate triangles TR in the crown 6. A plurality of (two) approximate triangles TR are formed in the sole 8. A third approximate triangle TR3 and a fourth approximate triangle TR4 are formed as the approximate triangles TR in the sole 8. The four approximate triangles TR are formed in the head structure portion s1.

One approximate quadrangle QU is formed in the crown 6. A first approximate quadrangle QU1 is formed as the approximate quadrangle QU in the crown 6. A plurality of (two) approximate quadrangles QU are formed in the sole 8. A second approximate quadrangle QU2 and a third approximate quadrangle QU3 are formed as the approximate quadrangles QU in the sole 8. The three approximate quadrangles QU are formed in the head structure portion s1.

The head structure portion s1 includes a first shape portion 401 having a shape corresponding to the first constituent face 301, and second shape portions 402 each having a shape corresponding to the second constituent face 302. The head structure portion s1 further includes third shape portions 403 each having a shape corresponding to the third constituent face 303. The following describes, as an example, a case where the first constituent face 301 is a triangle as in FIG. 15B (see FIGS. 16-17).

When a triangle is selected as the first constituent face 301, the shape corresponding to the first constituent face 301 is an approximate triangle TR, and the shape corresponding to the second constituent face 302 is an approximate quadrangle QU. When a plurality of approximate triangles TR are present as in the present embodiment, any one of the approximate triangles TR may be the first shape portion 401.

For example, the third approximate triangle TR3 located on the back side of the sole 8 is selected as the first shape portion 401. The three extending portions E1 located to surround the third approximate triangle TR3 constitute the first shape portion 401. In this case, the second shape portions 402 are the first approximate quadrangle QU1, the second approximate quadrangle QU2, and the third approximate quadrangle QU3. In this case, the third shape portions 403 are the first approximate triangle TR1, the second approximate triangle TR2, and the fourth approximate triangle TR4.

FIG. 17 shows correspondence between the embodiment of FIG. 16 and the cuboctahedron 300. In FIG. 17, corresponding portions are denoted with the same reference signs. That is, the first constituent face 301 and the first shape portion 401 are denoted by A, the second constituent faces 302 and the second shape portions 402 are denoted by B, and the third constituent faces 303 and the third shape portions 403 are denoted by C.

Alternatively, for example, the first approximate quadrangle QU1 may be selected as the first shape portion. In this case, the first approximate triangle TR1, the second approximate triangle TR2, and the third approximate triangle TR3 are the second shape portions, and the second approximate quadrangle QU2 and the third approximate quadrangle QU3 are the third shape portions.

Thus, the semi-regular polyhedral (cuboctahedral) structure is also incorporated into the head structure portion s1 and the rib frame 20 of the head 200.

The semi-regular polyhedron has a high shape stability. Such a head structure portion into which the semi-regular polyhedral structure is incorporated can efficiently enhance strength and durability of the head while reducing the head weight. Furthermore, such a rib frame to which the semi-regular polyhedral structure is applied effectively disperses stress and prevent stress from concentrating even when the rib frame is largely deformed. Therefore, it is possible to design a head that has a large elastic deformation amount and is excellent in strength. The large elastic deformation amount contributes to improvement in rebound performance.

[Triangular Portion]

In the above-described heads 2 and 200, the rib frame 20 includes triangular portions. A triangular portion of the rib frame 20 is formed by three extending portions E1 located to surround an approximate triangle TR.

In the head 2 of the first embodiment, the head structure portion s1 includes the six approximate triangles TR and consequently includes six triangular portions. Among these, triangular portions of the rib frame 20 are the second approximate triangle TR2, the third approximate triangle TR3, the fourth approximate triangle TR4, and the sixth approximate triangle TR6 (see FIGS. 5 and 7). The triangular portions of the rib frame 20 are triangular portions that are formed only by extending portions E1.

In the head 200 of the second embodiment, the head structure portion s1 includes the four approximate triangles TR and consequently includes four triangular portions. Among these, the third approximate triangle TR3 is the triangular portion of the rib frame 20.

The triangle has a high shape stability. The presence of the triangular portions can efficiently enhance strength and durability of the head while reducing the head weight.

From the standpoint of enhancing the effects of the triangular portions, the number of triangular portions included in the head structure portion s1 is preferably one or more, more preferably two or more, and still more preferably three or more. In view of the head weight, it is preferable that the number of the triangular portions which tend to make the rib frame dense is not excessively large. From this standpoint, the number of the triangular portions included in the head structure portion s1 is preferably ten or less, and more preferably eight or less.

From the standpoint of enhancing the effects of the triangular portions, the number of triangular portions included in the rib frame 20 is preferably one or more, more preferably two or more, and still more preferably three or more. In view of the weight of the rib frame, it is preferable that the number of the triangular portions which tend to make the rib frame dense is not excessively large. From this standpoint, the number of the triangular portions included in the rib frame 20 is preferably eight or less, and more preferably six or less.

An extending portion E1 whose both ends are connected to the striking face forming portion 14 is also referred to as a both-end-connected extending portion. Both the heads 2 and 200 include the both-end-connected extending portion. In the head 2, the first extending portion E11, the second extending portion E12, the third extending portion E13, and the fifth extending portion E15 are the both-end-connected extending portions. In the head 200, the first extending portion E11, the second extending portion E12, and the third extending portion E13 are the both-end-connected extending portions. All the extending portions E1 of the head 200 are the both-end-connected extending portions.

The both-end-connected extending portion can effectively receive an impact force applied to the striking face 4 and effectively disperse stress generated by the impact force. The both-end-connected extending portion can further enhance the effects of the rib frame 20. Furthermore, the both-end-connected extending portion can efficiently transmit recovery deformation to the striking face 4 after elastic deformation caused by hitting a ball. Therefore, the both-end-connected extending portion can contribute to improvement in rebound performance.

Both the heads 2 and 200 include a both-end-connected extending portion that continuously extend from the crown 6 into the sole 8. The both-end-connected extending portion continuously extending from the crown 6 into the sole 8 achieves effective reinforcement.

By increasing the length of the both-end-connected extending portion, a head having a large volume can be effectively reinforced. From this standpoint, the length of the both-end-connected extending portion is preferably equal to or greater than 150 mm, more preferably equal to or greater than 170 mm, and still more preferably equal to or greater than 190 mm. In view of the upper limit of the head volume specified by the golf rule, the length of the both-end-connected extending portion is preferably equal to or less than 300 mm, and more preferably equal to or less than 250 mm.

From the standpoint of strength of the rib frame 20, the number of the intersection portions 22 at which two extending portions E1 intersect is preferably two or more, more preferably three or more, and still more preferably four or more. From the standpoint of reducing the weight of the rib frame 20, the number of the intersection portions 22 at which two extending portions E1 intersect is preferably 15 or less, more preferably 13 or less, and still more preferably 11 or less.

FIG. 18 is a schematic diagram of a head structure portion s11 to which an icosidodecahedral structure is applied. FIG. 18 shows the head structure portion s11 as viewed from the back side, similar to FIG. 14. The striking face forming portion 14 is represented by a circle, and straight lines that each connect two points on the circle represent extending portions E1. Five extending portions E1 are provided in FIG. 18. At least one end of each extending portion E1 is connected to the striking face forming portion 14. That is, all the extending portions E1 extend from the striking face forming portion 14. Further, all the extending portions E1 are the both-end-connected extending portions. This structure is similar to the head structure portion s1 of the head 2.

Similar to the head structure portion s1 of the head 2, the embodiment of FIG. 18 includes a plurality of approximate pentagons PE and a plurality of approximate triangles TR. Among these, for example, the approximate triangle TR emphasized with bold dashed lines is a triangular portion that is formed by three extending portions E1. This triangular portion is formed by the three extending portions E1 extending from the striking face forming portion 14. The triangular portion is formed by three both-end-connected extending portions.

FIG. 19 is a schematic diagram of a head structure portion s12 to which a cuboctahedral structure is applied. FIG. 19 shows the head structure portion s12 as viewed from the back side. The striking face forming portion 14 is represented by a circle, and straight lines that each connect two points on the circle represent the extending portions E1. Three extending portions E1 are provided in FIG. 19. At least one end of each extending portion E1 is connected to the striking face forming portion 14. That is, all the extending portions E1 extend from the striking face forming portion 14. Further, all the extending portions E1 are the both-end-connected extending portions. This structure is similar to the head structure portion s1 of the head 200.

Similar to the head structure portion s1 of the head 200, the embodiment of FIG. 19 includes a plurality of approximate quadrangles QU and a plurality of approximate triangles TR. Among these, for example, the approximate triangle TR emphasized with bold dashed lines is a triangular portion that is formed by three extending portions E1. This triangular portion is formed by the three extending portions E1 extending from the striking face forming portion 14. The triangular portion is formed by three both-end-connected extending portions.

FIG. 20 is a schematic diagram of a head structure portion s13 to which a rhombicuboctahedral structure is applied. FIG. 20 shows the head structure portion s13 as viewed from the back side. The striking face forming portion 14 is represented by an outer circumferential circle. Straight lines that each connect two points on the outer circumferential circle, and a circle that is located on the inner side of the striking face forming portion 14 represent the extending portions E1. Five extending portions E1 are provided in FIG. 20. Except for the circular extending portion E1, at least one end of each of the remaining four extending portions E1 are connected to the striking face forming portion 14. That is, these four extending portions E1 extend from the striking face forming portion 14. These four extending portions E1 are the both-end-connected extending portions. The circular extending portion E1 does not extend starting from the striking face forming portion 14.

The embodiment of FIG. 20 includes a plurality of approximate quadrangles QU and a plurality of approximate triangles TR. Among these, for example, the approximate triangle TR emphasized with bold dashed lines is a triangular portion that is formed by three extending portions E1. This triangular portion is formed by two extending portions E1 extending from the striking face forming portion 14 and one extending portion E1 that does not extend from the striking face forming portion 14.

For the structures of the embodiments in FIGS. 18 to 20, a semi-regular polyhedron is cut in half to obtain the cut section used as the striking face 4. These structures are preferable because stable shapes of the respective semi-regular polyhedrons can be effectively incorporated into the structures.

Note that, in the icosidodecahedron and the cuboctahedron, by electing one first constituent face, the second constituent face is determined to one type of polygon. For example, in the icosidodecahedron, when a triangle is elected as the first constituent face, the second constituent face is determined to one type of polygon, that is, a pentagon. However, depending on the type of semi-regular polyhedron, the number of types of polygons for the second constituent faces might be two or more. For example, in the rhombicuboctahedron, when the first constituent face has a shape of a quadrangle, the second constituent faces have respective shapes of a triangle and a quadrangle. Also, for example, in the truncated icosahedron, when the first constituent face has a shape of a hexagon, the second constituent faces have respective shapes of a pentagon and a hexagon. Similarly, depending on the type of semi-regular polyhedron, the number of types of polygons for the third constituent faces might be two or more. From the standpoint of shape stability, the semi-regular polyhedron is preferably the icosidodecahedron or the cuboctahedron. The icosidodecahedron is particularly preferable in view of making the curvature of the extending portions E1 relatively small and reducing the number of the extending portions E1.

Of the three extending portions E1 which form the triangular portion, at least two extending portions E1 preferably extend starting from the striking face forming portion 14. In this case, an impact force applied to the striking face is effectively transmitted to the triangular portion, and therefore the function of the triangular portion is more effectively exhibited. From this standpoint, the three extending portions E1 forming the triangular portion preferably extend starting from the striking face forming portion 14, and more preferably are the both-end-connected extending portions.

The presence of the second shape portion increases the degree of similarity to the semi-regular polyhedron. From this standpoint, at least one second shape portion is preferably present. The degree of similarity to the semi-regular polyhedron increases as the number of the second shape portions increases. From this standpoint, the number N2 of the second shape portions is preferably two or more, more preferably three or more, and still more preferably four or more. The number N2 is most preferably the above-described maximum possible number. The shape of the first constituent face and the position of the first shape portion may be determined to maximize the number N2.

The presence of the third shape portion increases the degree of similarity to the semi-regular polyhedron. From this standpoint, at least one third shape portion is preferably present. The degree of similarity to the semi-regular polyhedron increases as the number of the third shape portions increases. From this standpoint, the number N3 of the third shape portions is preferably two or more, and more preferably three or more. The number N3 is most preferably the above-described maximum possible number. The shape of the first constituent face and the position of the first shape portion may be determined to maximize the number N3.

In the heads 2 and 200, the rib frame 20 is formed in both the crown 6 and the sole 8. The whole head can be effectively reinforced by this configuration. Alternatively, the rib frame 20 may be provided in only one of the crown 6 and the sole 8. This configuration can improve design freedom of the head. For example, the rib frame 20 may be provided only in the crown 6, and a crown cover member made of a CFRP may be glued to the rib frame 20. In this case, the weight of the crown 6 can be reduced to lower the center of gravity of the head. Alternatively, the rib frame 20 may be provided only in the sole 8, and a sole cover member made of a CFRP may be glued to the rib frame 20. In this case, the weight of the sole 8 can be reduced to raise the center of gravity of the head.

The rib frame 20 may be hidden inside the head. Alternatively, the rib frame 20 may be exposed.

FIGS. 21A to 21F are cross-sectional views showing variations of the configuration of the extending portion E1.

In the embodiment of FIG. 21A, the extending portion E1 is integrally formed with an outer shell portion G1 of the head. The extending portion E1 is provided on the inner surface of the head. The extending portion E1 is a protruding portion protruding from the inner surface of the outer shell portion G1. In this case, the extending portion E1 is also a thick portion.

In the embodiment of FIG. 21B, the extending portion E1 is a member that is formed separately from the outer shell portion G1 of the head. The extending portion E1 is joined to the inner surface of the outer shell portion G1. The structure of FIG. 21B is employed in the above-described head 2. In the head 2, the cover member c1, which is the outer shell portion G1, is joined to the extending portion E1 by using an adhesive agent.

In the embodiment of FIG. 21C, the extending portion E1 is integrally formed with the outer shell portion G1 of the head. That is, the extending portion E1 is a thick portion. The extending portion E1 is provided on the outer surface of the head. The extending portion E1 is a protruding portion protruding from the outer surface of the outer shell portion G1.

In the embodiment of FIG. 21D, the extending portion E1 is a member that is formed separately from the outer shell portion G1 of the head. The extending portion E1 is joined to the outer surface of the outer shell portion G1.

In the embodiment of FIG. 21E, the extending portion E1 is integrally formed with the outer shell portion G1 of the head. That is, the extending portion E1 is a thick portion. The extending portion E1 is provided on the outer surface and the inner surface of the head.

In the embodiments of FIGS. 21A to 21E, the rib frame 20 is disposed along the outer shell portion G1. In FIGS. 21A and 21B, the rib frame 20 is disposed along the inner surface of the outer shell portion G1. In FIGS. 21C and 21D, the rib frame 20 is disposed along the outer surface of the outer shell portion G1. In FIG. 21E, the rib frame 20 is disposed along the inner surface and the outer surface of the outer shell portion G1. In the embodiments of FIGS. 21A to 21E, the outer shell portion G1 can be effectively reinforced by the rib frame 20.

In the embodiment of FIG. 21F, the extending portion E1 is not disposed along the outer shell portion G1. This embodiment does not include the outer shell portion G1 that is directly reinforced by the extending portion E1. For example, a head structure portion s1 which does not include the cover member c1 (see FIGS. 2 and 13) as it is may serve as the finished head. From the standpoint of strength, a surface (such as the outer shell portion G1) that bridges spaces between the extending portions E1 is preferably provided.

The following clauses are disclosed regarding the above-described embodiments.

[Clause 1]

A golf club head comprising:

a striking face forming portion; and

a rib frame that is constituted by a plurality of extending portions, wherein

the rib frame and the striking face forming portion constitute a head structure portion, and

the head structure portion includes:

a first shape portion having a shape corresponding to a first constituent face that is arbitrarily selected from a semi-regular polyhedron; and

a second shape portion having a shape corresponding to a second constituent face that shares one side with the first constituent face in the semi-regular polyhedron.

[Clause 2]

The golf club head according to clause 1, wherein the first constituent face is a triangle, a quadrangle, or a pentagon.

[Clause 3]

The golf club head according to clause 1 or 2, wherein the semi-regular polyhedron is an icosidodecahedron or a cuboctahedron.

[Clause 4]

A golf club head comprising:

a striking face forming portion; and

a rib frame that is constituted by at least three extending portions, wherein

the rib frame includes a triangular portion that has a shape corresponding to a triangle.

[Clause 5]

The golf club head according to clause 4, wherein

the at least three extending portions include three extending portions forming the triangular portion, and

of the three extending portions forming the triangular portion, at least two extending portions extend from the striking face forming portion.

[Clause 6]

The golf club head according to clause 4, wherein

the at least three extending portions include three extending portions forming the triangular portion, and

the three extending portions forming the triangular portion extend from the striking face forming portion.

[Clause 7]

The golf club head according to any one of clauses 1 to 6, wherein

the head includes an outer shell portion and a hollow portion, and

the rib frame is disposed along the outer shell portion.

[Clause 8]

The golf club head according to any one of clauses 1 to 7, wherein

the head includes a crown and a sole, and

the rib frame is formed in the crown and the sole.

[Clause 9]

The golf club head according to any one of clauses 1 to 7, wherein

the head includes a crown and a sole, and

the rib frame is formed in only one of the crown and the sole.

The above description is merely illustrative and various modifications can be made without departing from the principles of the present disclosure. 

What is claimed is:
 1. A golf club head comprising: a striking face forming portion; and a rib frame that is constituted by a plurality of extending portions, wherein the rib frame and the striking face forming portion constitute a head structure portion, and the head structure portion includes: a first shape portion having a shape corresponding to a first constituent face that is arbitrarily selected from a semi-regular polyhedron; and at least one second shape portion having a shape corresponding to at least one second constituent face that shares one side with the first constituent face in the semi-regular polyhedron.
 2. The golf club head according to claim 1, wherein the first constituent face is a triangle, a quadrangle, or a pentagon.
 3. The golf club head according to claim 1, wherein the semi-regular polyhedron is an icosidodecahedron or a cuboctahedron.
 4. A golf club head comprising: a striking face forming portion; and a rib frame that is constituted by at least three extending portions, wherein the rib frame includes a triangular portion that has a shape corresponding to a triangle.
 5. The golf club head according to claim 4, wherein the at least three extending portions include three extending portions forming the triangular portion, and of the three extending portions forming the triangular portion, at least two extending portions extend from the striking face forming portion.
 6. The golf club head according to claim 4, wherein the at least three extending portions include three extending portions forming the triangular portion, and the three extending portions forming the triangular portion extend from the striking face forming portion.
 7. The golf club head according to claim 1, wherein the head includes an outer shell portion and a hollow portion, and the rib frame is disposed along the outer shell portion.
 8. The golf club head according to claim 1, wherein the head includes a crown and a sole, and the rib frame is formed in the crown and the sole.
 9. The golf club head according to claim 1, wherein the head includes a crown and a sole, and the rib frame is formed in only one of the crown and the sole.
 10. The golf club head according to claim 1, wherein the semi-regular polyhedron is an icosidodecahedron.
 11. The golf club head according to claim 1, wherein the number of the at least one second shape portion is two or more.
 12. The golf club head according to claim 1, wherein the number of the at least one second shape portion is three or more.
 13. The golf club head according to claim 1, wherein the number of the at least one second shape portion is a maximum possible number, and when the first constituent face is an n-sided polygon, the maximum possible number is defined as n.
 14. The golf club head according to claim 1, wherein the at least one second constituent face comprises at least two second constituent faces, the head structure portion further includes at least one third shape portion having a shape corresponding to a third constituent face, the third constituent face being a constituent face of the semi-regular polyhedron other than the first constituent face and the second constituent faces and having two sides respectively shared with two second constituent faces adjacent to each other.
 15. The golf club head according to claim 14, wherein the number of the at least one third shape portion is two or more.
 16. The golf club head according to claim 14, wherein the number of the at least one third shape portion is three or more.
 17. The golf club head according to claim 7, wherein the plurality of extending portions of the rib frame are disposed on an inner surface of the outer shell portion. 